This invention relates to balance weights for vehicle wheels, in particular those of automobiles and trucks. More specifically, this invention relates to wheel balance weights of the clip type which are attached to rims upon which tires are mounted.
A number of prior means have been used to balance wheels of automobiles and trucks, including wheel balance weights which attach to the rim by clips, adhesives, inserts into grooves, or other means. Hub caps and wheel covers also have been used to balance wheel assemblies, as have dynamic balancers which attach internally or externally to the tire/wheel assembly and have a mass which moves to balance the wheel after the wheel turns at a certain speed. Some of these and other means are disclosed in U.S. Pat. Nos. 2,433,762; 3,495,877; 3,669,500; 4,591,210; 4,720,149; 4,728,154 and 4,755,006; and Italian patent No. 646,067. Each means has its own inherent advantages and disadvantages relating to such criteria as standardization, cost, appearance, performance, ease of manufacture, ease of use, etc.
In particular, as to wheel balance weights of the clip type, a resilient clip is attached to a lead weight configured to nest under the flange of the rim so that centrifugal force will not throw the weight off from the rim at high wheel speeds. The clip in turn attaches the weight to the rim. A disadvantage of the present clip-on weights is that the unloaded gap dimension between the clip and lead weight, prior to clipping onto the rim, must be within a certain range to fit a given rim flange thickness. If the gap is too small, the weight and clip will be difficult to attach to the rim, and if forced onto the rim, the clip will be sprung such that poor weight retention will result. On the other hand, if the unloaded gap dimension between the clip and lead weight is too large, the result equally will be poor retention. As a further complicating factor, rim flange thicknesses and contours vary. Accordingly, different clip-type weights having different unloaded gap dimensions between the clip and weight must be manufactured and inventoried in order to accommodate the different rim flange thicknesses and contours. Excessive ordering, inventory, and carrying costs can result. Further, confusion can arise as to which gap dimensions fit which rim flanges in various circumstances.
Certain attempts have been made to solve the above-described problems of clip-type weights, one being described in U.S. Pat. No. 4,728,154 wherein two clips are respectively provided on opposite sides of the weight to provide two different gap dimensions. The particular gap dimension selected depends on which of two mounting positions is selected for the balance weight under the rim flange. This has the disadvantage of needing to select one of the two gap dimensions and needing to orient the balance weight before attaching to the rim, regardless of whether the weight is applied by hand or automated equipment, and the cost of manufacturing and assembling the clip would be greater than that of previously-known clip-type weights. Other variations to solve the above clip-type weight problems are shown in U.S. Pat. No. 3,495,877, having abradable protrusions on the lead balance weight which can be removed to a greater or lesser degree to fit different rim flange thicknesses, or having a separate spring part next to the weight so that rim flanges of different thicknesses can be held between two springs; and, U.S. Pat. No. 3,669,500, having a balance weight with a separate adjustable holding clip rather than an integral holding clip. Both of these variations have apparent manufacturing and/or assembly disadvantages.